Method of and mechanism for cleansing the inked surfaces of engraving plates



ATTORNEY P. AITCHISON METHOD OF AND MECHANISM FOR CLEANSING THE INKEDSURFACES OF ENGRAVING PLATES Filed Dec. 2, 1927 Sept, 19, 1933.

Patented Sept. 19, 1933 cum-E 'sm METHOD or AND MECHANISM FOR CLEANSINGTHE INKED SURFACES 0F ENGRAVING PLATES Peter A itchison, New Rochelle,N. Y., assignor to American Bank Note Company, New York, N. Y., acorporation of New York Application December 2,1927. Serial No. 237,147I I 6'Claims; (01. 101-156 My invention relates to the method of, andmechanism for cleansing the inked surfaces of engraving plates, and moreparticularly to a method of removing the ink from the non-printingsurface of the plate, and to a type of such mechanism using a continuousweb-of wiping material adapted to be engaged with the face of a printingplate prior to the making of each impression therefrom;

Heretofore, it has been the common practice, in connection withundersurface printing machines of various ltypes, to use a wipingmechanism embodying therein a platen across which is intermittently feda continuous web of 'a rough fabric capable of removing the ink from thenon-printing surface of a plate in a manner to utilize a portion of thesurface ink for ensuring a complete filling of the intaglio lines in theplate. Where a printing press is equipped only with a wiping mechanism,this web, or as it is termed in the art, ragfi has ordinarily been inthe nature of burlap. When mechanical polishing has been resorted to,the material used for the polishing Web has been a muslin. Various othermaterials have been used for the wiping and polishing webs or strips,and it has long been the common practice, in embossing machines, to wipethe steel dies used in such machines with a paper strip passing over aplaten, and fed intermittently after each disengagement of the platewith the paper covered platen.

' With the above conditions in mind, I have provided a wiping mechanismfor steel plate or undersurface printing machines in which the use of.burlap', muslin'or other cloths may be dispensed with, and strip papersubstituted therefor,

With" the use of such paper, the necessity for Washing or launderingcloths after they have been once run through a press is avoided, acomplete filling of the lines of a plate is secured,'and the platesmaybe very effectively wiped and polished. With the use of burlap andmuslin webs, it has been found, desirable to close a clamping mechanismupon, the wiping web between the supply roll of same and the wiping orpolishing platen to ensure against the wrinkling or creeping of thecloth during the wiping or polishing operation, but with a paper web theuse of such a clamping mechanism has not only been found unnecessarybut'undesirable.

: While in the past, I have used various grades and finishes or softpaper for wiping and polishing webs, I find thattheflbest results can besecured by a heavy grade of rough soft paper such as is commonlyused.for toweling, since such appears to possess sufficient strength to bereadily fed through the machine while withstanding the effect of therubbing contact between same and the printing plate, and possessessufiicient absorptive power to remove the surface ink by capillaryattraction, but sufficiently slowly to ensure that piling of the ink atthe juncture of en'- gagement of thewiping strip and the plate necessaryto an adequate filling of the lines of the plate with ink. At the sametime, this paper is not sufficiently flexible to be forced intothe-lines of the plate with a resultant extraction of any materialportion of the ink from even the wider lines. I

' The invention consists in the novel steps and practices by which inkupon the top or nonprinting surface of anengraved, intaglio or undersurface printing plate is in part packed in the lines of the designandv excess ink is removed, and in the novel features of constructionand combination of parts of the mechanism employed, all as hereinafterset forth and described and more particularly pointed out in the claimsheretoa-ppended. Referring to the drawing,

Fig. 1 is a diagrammatic showing of the wiping mechanism of a rotaryundersurface printing non-printing surface of the plate by reason of themultitude of contacting areas.

The material used is a paper, the finish of which is similar to what isknown as crepe paper,

although the paper itself is of a stock sufliciently thick and strong toadmit of the relative action between same and the plate, and thedevelopment of the desired pressure without mutilation of the web orstrip. The ridges upon the paper extend generally transversely of thelength of the operation by a series of succeeding. wiping actions vchine carrying two plates 1) and c.

and affords space for the accumulation of the ink in advance of eachridge, desirable in filling the lines of the design with ink.Furthermore, the spaced points of contact preclude the development ofsuction in a manner to tend to lift ink from the lines.

The material of the strip or web is such as to impart to it lowabsorptive properties, essential to permit the use of a small quantityof ink as compared with that required when employing other methods andmaterials during the wiping operation incidental to the making of animpression.

Referring to the drawing, a indicates the plate cylinder of a rotaryundersurface printing ma- Associated with this cylinder is a cam (1,having two risers d and (1 so positioned as to operate the wiper webfeeding mechanism e following the wiping of each plate.

The inking mechanism isshown conventionally at f. The st'ripor webfeeding mechanism e is shown merely conventionally, as are the paper websupport 9, the re-wind reel h and the means i operative upon saidre-wind reel and acted upon by the web feeding mechanism.

In the accompanying drawing, I have shown merely a wiping mechanism, itbeing understood that, if desired, the various mechanisms hereindescribed may be duplicated at a point where they will operate upon theplate between the wiping mechanism and the printing line. The wipingmechanism herein shown, comprises two platens a and 7c, suitably paddedto have present in the platen the usual resiliency. Each of theseplatens is spring pressed toward the axis of the plate cylinder in theusual manner. Between the platen 9 and the support for the supply reelof the web is a guide roller m; between the platen 7c-and the re-windreel is a guide roller 11, and betreen the two platens 9' and k is aguide roller 0.

The supply roll of the paper web is indicated at p, and the portion ofthe paper from this web in its run through the re-wind reel is indicatedt pr The wiping strip or web used is soft, absorbent paper stock, suchas is commonly used for toweling, having a rough grained surface, thegeneral ent, it will fail to properly pack the lines of the 1 plate andwill, particularly as to the hair lines, pull some of the ink therefromso that a sharp clear imprint cannot be secured. The grain should not beraised-too high, as this will tend to the formation of wrinkles in thepaper, which wrinkles will cause excessive thickness and compactionthereof within limited areas and result in an improper wiping of otherportions of the plate than wherethese wrinkles engage.

I have used various kinds and. weights of paper, but have found that theso-called paper toweling gives the best results, and I attribute this tothe greater absorptive properties of this paper and the. short, slightlyraised graining effect By advancing the wiping strip or web of paper oftheir having already been partially saturated with ink as a result ofthe wiping of previous plates. The totally unsaturated portion of thepaper will, throughout the wiping action of each plate, pick up the inkso slowly as to cause the piling thereof in advance of the platen andthus effectively pack the lines of the plate. The partially saturatedportions of the strip or web of paper will absorb the ink much morerapidly than the totally unsaturated portion thereof, al-

though the latter will be partially saturated upon the completion of thewiping of any plate.

In order to secure an effective wiping action by the paper, I have foundit necessary to reduce thequantity of ink applied to a plate, since anover-supp1y of ink upon the nonprinting or top surface of the plate willhave the effect of too rapidly saturating the paper so that an im-.perfect wiping results, and a smudgy, streaky imprint follows. V

If the graining effect of the paper be too heavy, in addition to thetendency toward the formation of wrinkles, there will also be a tendencyof the paper to stretch during the rubbing coritact of the platetherewith which will interfere materially with the proper wiping orpolishing action.

The general direction of the grain in the paper strip or web must beparallel with the axis of the plate cylinder to avoid streaking of theplate. I

With the short graining of the paper the elevated portions will notextend continuously from edge to edge of the paper, butwill beirregularly arranged in a general parallel relation to each other so asto preclude the presence of any channels extending parallel about thecircumference of the plate for a suflicient distance to leave anyunwiped streaks upon the plate.

To one skilled in the art, the general mode of operation will be readilyunderstood. 7

After the making of each impression, each plate I) or c has ink appliedthereto by the'rollers of the inking mechanism some of the ink enteringthe intaglio lines of the plate, and the rest of the ink remaining uponthe top or'n'onprinting surface. Asthe plate leaves the inkingmechanism, the forward edge engages that 'por- I tion of the paper stripor'web'p, passing over the platen 7, which latter, by reason of itsresiliency, conforms to the curvature of the plate and yields in theusual manner to control the pressure relation between'thepaper strip orweb and the plate. p

As heretofore stated, the first portion-of the paper strip or webengaged by the forward edgeof the plate will be clean or entirelyunsaturated with ink, the length of this portion corresponding with thequantity of feeding movement of the strip or web with each actuation ofthe mechanism e. The succeeding portion of the paper strip or webengaged by the plate will be partially saturated, thus taking up inkmore readily than does the clean portion of the strip or web.

After leaving the portion of the strip. or web passing about the platena, the plate engages theportion of said stripv'or web passing about theplaten is, which is more fully saturated than any portion of said stripor web passing about the platen 7'. With the continued movement of theplate in relation to the platen 7, ink upon the non-printing surface ofthe plate will be accumulated at each changing point of juncture withthe paper web or strip so as to afford a slight accumulation of ink, aconsiderable portion of which will be forced into the lines of theplate, and the remainder of which will be gradually absorbed by thestrip or Web.

By the time the rear edge of the plate passes the platen 7', the firstportion of the strip or web to be engaged by the plate will haveabsorbed the surplus ink not required for packing the lines. The more orless extended areas of the platens 7' and k are merely to ensure thecomplete removal of ink from the non-printing surface of the plate.

The presence of previously absorbed ink in the paper toward the end ofthe wiping action, and

the pressure relation of the platen and the cylinder has the effect ofrestricting the pickup of the ink by the strip or web to the ink uponthe top or non-printing surface of the plate, and the short irregulargrain will check the development of any such suction as would tend tolift the ink from the lines of the plate, even the finer lines.

Immediately that the rear edge of the plate passes through engagingrelation with the platen k, the riser d of the cam d will actuate themechanism 6 and thus draw paper from the roll p and advance the run pthereof in the direction of movement of the plate, preparatory to thewiping operation upon the succeeding plate 0.

Upon the completion of the wiping of this plate, the riser cl of the cam01 will again advance the strip or Web in the same manner andto the sameextent. In this manner, a clean short length of the paper strip or webis presented to the following plate after each inking. The quantity ofthis feeding movement is such that a considerable portion of thewipingis done by portions of the paper strip or web which have already beenused to help wipe two or more plates. v.

It is not my intention to limit the invention to the precise details ofconstruction shown in the drawing, it being apparent that such may bevaried without departing from the spirit and scope of the invention.

Having described the invention, what I claim as new and desire to haveprotected by Letters Patent, is:

1. A wiping mechanism for undersurface printing machines, embodyingtherein a support, a roll of a continuous strip or web of roughabsorbent wiping paper rotatably mounted on said support, a wipingplaten, guiding means for the paper strip between said support and saidplaten, a re-wind reel, guiding'means for the paper strip between saidreel support and said rewind reel,

an inking mechanism, and intermittently actudistance less than thelength of the plates to be wiped upon the disengagement of the platefrom the strip or web.

2. A wiping mechanism for undersurface printing machines, embodyingtherein a support, a roll of a continuous strip or web of absorbentpaper having a raised granular surface extending transversely of thestrip or web rotatably mounted on said support, a wiping platen, guidingmeans for the paper strip between said support and said platen, are-wind reel, guiding means for the paper strip between said reelsupport and said re-wind reel, an inking mechanism, and intermittentlyactuated means advancing said paper strip or web a distance less thanthe length of the plates to be wiped upon the disengagement of the platefrom the strip or web.

3. A wiping mechanism for undersurface printing machines, embodyingtherein a support, a roll of a continuous strip or web of absorbentpaper having a raised granular surf ace'extending transversely of thestrip or web rotatably mounted on said support, the graining of thepaper consisting of short elevated portions irregularly arranged in ageneral parallel relation to each other, a wiping platen, guiding meansfor the paper strip between said support and said platen, a re-windreel, guiding means for the paper strip between said reel support andsaid re-wind reel, an inking mechanism, and intermittently actuatedmeans advancing said paper strip or Web a distance less than the lengthof the plates to be wiped upon, the disengagement of the plate from thestrip or web.

4. The method of cleansing the ink surfaces of engraving plates and thelike which consists in passing over the ink surface a flexible materialhaving spaced projections on the surface thereof in such manner that theprojections only contact the ink surface.

5. The method of removing undesirable ink from inky surfaces ofengraving plates, cylinders, and the like which consists in relativelypassing over the ink surface flexible material having a ridged surfaceof an absorbent nature, the ridges being spaced and the materialoperating on the inky surface with ridges only in en-' gagement with theinky surface during relative movement of the flexible material over theinky surface. t

6. The method of cleansing theinked surfaces of engraving plates. andthe like which consists in passing over the inked surface a flexiblecrepe like absorbent ink wiping paper having closely spaced raisedprojections thereon, in such manner that the raised projections onlywill contact with the inked surface.

PETER AITC HISON.

ated means advancing said paper strip or web a

